For the past several years, a variety of Group Special Mobile (GSM) network operators have expressed the need for the ability to determine the position of a mobile station to allow them to offer services based on the location of the mobile station. Examples of such services are location-sensitive billing and location-based yellow pages services. Such services must provide the mobile station's position with enough precision to allow the network operator to offer a meaningful network service. In addition, the Federal Communications Commission in the United States has mandated as part of Docket 94-102 that wireless network operators be able to provide the position of a mobile station to within 125 meters 67% of the time by April 2001.
Currently, no solution exists in GSM for determining the position of a mobile station with the assistance of the mobile, nor with the assistance of an adjunct radio device. The positioning solution must support the ability to determine the position of the mobile station in the following cases:
A request by the mobile station to the network for the mobile station's position. This must be supported when the mobile station is engaged in a call and when the mobile is in idle mode, not engaged in a call.
A request by service logic in the network for the position of a mobile. In particular, the solution must support the determination of a mobile station's position within a CAMEL call.
A request by an external location services application for the location of a mobile station. The network must be able to determine the position of the mobile station and return the position to the external application either within a call or independent of a call. This external application is service logic that resides outside the GSM network's boundaries.
An emergency call by a mobile station. The network must determine the position of the mobile station during call setup to allow service logic associated with the emergency number to route the call to the appropriate destination. The network architecture must support ability to determine the position of the mobile station within the objective set by the FCC in Docket 94-102, 125 meters.
To accomplish this, the GSM network requires a new network element and new capabilities in the network:
A new network element to calculate the position of the mobile station,
New procedures in existing GSM network elements to support positioning,
Extensions of the protocols between these network elements to convey position-related information between the network elements.